I went to the White House shortly after tea where I found "the original gorilla," about as intelligent as ever. What a specimen to be at the head of our affairs now!
Source, in full
Comment after meeting with President Abraham Lincoln, 17 November 1861, The Civil War Papers of George B. McClellan, p. 135. McClellan is said to have often used Edwin M. Stanton's term the "original gorilla" in referring to Lincoln.